Baily's beads definitions

Arc of bright spots seen during a total eclipse of the sun, named for Francis Baily (1774-1844), the English astronomer who first called attention to them. Just before the moon's disk completely covers the sun, the narrow crescent of sunlight may be broken in several places by mountains and valleys on the edge of the moon's disk; the resulting spots resemble a string of beads. The "diamond-ring effect" occurs when the very last rays of the sun to be obscured look like a bright diamond on the solar corona.

Baily's beads Bai"ly's beads (Astron.) A row of bright spots observed in connection with total eclipses of the sun. Just before and after a total eclipse, the slender, unobscured crescent of the sun's disk appears momentarily like a row of bright spots resembling a string of beads. The phenomenon (first fully described by Francis Baily, 1774 -- 1844) is thought to be an effect of irradiation, and of inequalities of the moon's edge.